Propulsion in a Fluid Medium.pptx Biomechanics II by Susan J. Hall DPT 4th Semester

Human Propulsion in a Fluid Medium Biomechanics II by Susan J. Hall DPT 4th Semester SZABMU

1. Propulsion in a Fluid Medium An In-depth Analysis of Propulsion Mechanics Presented by: Dr. Basil Wahab PT

2. Introduction to Propulsion in Fluid Medium Definition Propulsion in fluid mediums  refers to the mechanisms and forces that enable an object or organism to move through a fluid, such as water or air. This movement is achieved by generating thrust, which overcomes the resistive forces (like drag) exerted by the fluid.

3. Examples of propulsion Swimming, fish movement, flight in birds Importance in engineering (e.g., ship design, aircraft design) and biological systems

4. Propulsive Drag Theory Introduction Proposed by Counsilman and Silvia and is based on Newton’s third law of motion Propulsive drag occurs when an object moves through a fluid, experiencing resistance. Unlike general drag, propulsive drag is a result of the propulsion method itself.

5. Applications Swimmer’s hand positioning. Propeller design in ships and submarines.

6. Types of Drag in Propulsion Form Drag Caused by the shape of the object. Streamlined vs. bluff bodies. Skin Friction Drag Result of the fluid’s viscosity interacting with the surface. Significance in swimmers’ body suits and aircraft wing design. Wave Drag Occurs at the interface of two fluids, such as air and water. Important in high-speed marine vessels.

7. Propulsive Lift Theory Introduction Propulsive lift occurs when lift forces are utilized for propulsion, especially in fluid mediums. Proposed by Counsilman in 1971 Differentiates from traditional lift used for maintaining altitude.

8. Applications Aircraft wing design. Dolphin and whale swimming techniques .

9. Lift vs. Drag in Propulsion Comparison Lift-based propulsion is often more efficient in certain mediums. Trade-offs: Increased lift can lead to increased drag. Design considerations: Optimizing the balance for different applications (e.g., gliding vs. powered flight).

10. Vortex Generation Introduction Vortices are swirling flows that are generated as a result of propulsion. They play a critical role in enhancing thrust and efficiency.

11. Applications Jet propulsion in marine animals. Vortex generators in aircraft design to control boundary layer separation.

12. Impact of Vortex on Propulsion Efficiency Vortex Control Techniques to minimize unwanted vortex generation. Use of winglets in aircraft to reduce induced drag. Enhanced Propulsion Exploiting vortices for increased thrust, as seen in the undulating movements of fish. Impact on energy consumption and performance.

13. Stroke Technique Introduction Stroke technique refers to the specific movements used to generate propulsion in a fluid medium. Critical in swimming, rowing, and animal locomotion.

14. Examples Freestyle swimming technique. Butterfly stroke mechanics .

15. Biomechanics of Stroke Technique Human Swimming: Muscle groups involved: Shoulders, arms, core. Role of body rotation and arm mechanics. Analysis of elite swimmer techniques for optimal performance. Animal Locomotion: Fish undulatory swimming: Coordination of body waves for efficient movement. Bird wing strokes in flight: Balancing lift and thrust.

16. Practical Applications and Innovations of Propulsion in fluid Medium Engineering Design: Propulsion systems in aquatic vehicles. Innovations in low-drag and high-thrust designs. Sports Technology: Development of swimwear and equipment to reduce drag. Impact of technique optimization on athletic performance.

17. Challenges and Future Research Challenges: Balancing efficiency and power in propulsion systems. Environmental impacts of propulsion in marine systems (e.g., noise pollution). Future Research: Advancements in biomimicry: Learning from nature to develop better propulsion systems. Computational Fluid Dynamics (CFD): Predictive modeling for improved designs. Sustainable propulsion technologies.

18. References Basic Biomechanics by Susan J. Hall Ungerechts BE: On the relevance of rotating water fl ow for the propulsion in swimming. In Jonsson B, ed: Biomechanics X-B, Champaign, IL, 1987, Human Kinetics Publishers Van Ingen Schenau GJ: The influence of air friction in speed skating, J Biomech 15:449, 1982 Minetti AE, Machtsiras G, and Masters JC: The optimum fi nger spacing in human swimming, J Biomech 42:2188, 2009 McCullough AS, Kraemer WJ, Volek JS, Solomon-Hill GF Jr, Hatfi eld DL, Vingren JL, Ho JY, Fragala MS, Thomas GA, Häkkinen K, and Maresh CM: Factors affecting fl utter kicking speed in women who are competitive and recreational swimmers, J Strength Cond Res 23:2130, 2009 Maglischo E: Swimming faster: a comprehensive guide to the science of swimming , Palo Alto, CA, 1982, Mayfi eld Publishing Laffi te LP, Vilas-Boas JP, Demarle A, Silva J, Fernandes R, and Billat VL: Changes in physiological and stroke parameters during a maximal 400-m free swimming test in elite swimmers, Can J Appl Physiol 29 Suppl:S17, 2004

19. Thank You ! For not Asking Questions